Map - East St. Louis, Illinois (East Saint Louis)

East St. Louis is a city in St. Clair County, Illinois. It is directly across the Mississippi River from Downtown St. Louis, Missouri and the Gateway Arch National Park. East St. Louis is in the Metro-East region of Southern Illinois. Once a bustling industrial center, like many cities in the Rust Belt, East St. Louis was severely affected by the loss of jobs due to industrial restructuring during the second half of the 20th century. In 1950, East St. Louis was the fourth-largest city in Illinois when its population peaked at 82,366. As of the 2020 census, the city had a population of 18,469, less than one-quarter of the 1950 census and a decline of almost one third since 2010.

A recent addition to the city's waterfront is the Gateway Geyser. On the grounds of Malcolm W. Martin Memorial Park, the fountain is the second-tallest in the world. Designed to complement the Gateway Arch across the river in St. Louis, it shoots water to a height of 630 ft, the same height as the arch.

Native Americans had long inhabited both sides of the Mississippi River. The Mississippian culture rulers organized thousands of workers to construct complex earthwork mounds at what later became St. Louis and East St. Louis. The center of this culture was the urban complex of Cahokia, located to the north of present-day East St. Louis within Collinsville, Illinois. Before the Civil War, settlers reported up to 50 mounds in the area that became East St. Louis, but most were lost to 19th-century development and later roadbuilding.

East St. Louis lies within the fertile American Bottom area of the present day Metro-East area of St. Louis, Missouri. This name was given after the United States acquired the Louisiana Purchase in 1803, and more European Americans began to settle in the area. The village was first named "Illinoistown".

East St. Louis was founded in 1797 by Captain James Piggott, a Revolutionary War veteran. In that year Piggott began operating a ferry service across the Mississippi River, connecting Illinoistown with St. Louis, which had been founded by ethnic French families. When Piggott died in 1799, his widow sold the ferry business, moved to St. Louis County and remarried. One of the Piggotts' great-great-granddaughters became known as actress Virginia Mayo (Virginia Clara Jones).

The municipality called East St. Louis was established on April 1, 1861. Illinoistown residents voted on a new name that day, and 183 voted to rename the town East St. Louis. Though it started as a small town, East St. Louis soon grew to a larger city, influenced by the growing economy of St. Louis, which in 1870 was the fourth-largest city in the United States.